Novel artificial silk effects and process of producing same



Patented Apr. 23, 1935 NOVEL ARTIFICIAL SILK EFFECTS AND PROCESS OF PRGDUCING SAME Georges Heberleln, Wattwil, Switzerland, acsignor to Heberlein Patent Corporation, New York, N. Y., a corporation of New York No Drawing. Application May 18, 1929, Serial No. 364,337. In Germany January 15, 1926 4 Claims.

My invention relates to novel artificial silk effects and process of producing same. The object of the invention is to provide artificial silk goods having their physical characteristics changed or 5 altered in one or more respects, such as a change in the characteristic appearance and/or hand (touch). I use the term artificial silk in this specification and in the appended claims as designating the various forms of regenerated cellu- 10 lose such for example as artificial silks known as viscose, s'uprammonium and nitro cellulose silks, the latter being exemplified, for example, by those lmown in commerce as Chardonnet and 'Iubize; and as excluding acetate silk.

15 According to the invention, for example, artificial silk (regenerated cellulose but not acetate silk) may be so treated that the characteristic excessive lustre of artificial silk fabrics will partially or wholly disappear and the fabric will as- 20 sume a lustreless, transparent eifect, and become stifi'er to the touch. As will be more fully explained according to this invention, a variety of novel efiects in artificial silk may be obtained, and some of these effects are especially valuable in 25 the production of pattern effects on fabrics made entirely or partly of artificial silkfibres.

The process is applicable to artificial silk goods This is a continuation in part of application Ser. No. 161,022 filed January 13, 1927. The claims in the basic orparentcase are directly 35 broadly and specifically to a process for treatment of artificial silk to modify or eliminate the high lustre and-to produce increased stiffness and translucency in conjunction with the reduced lustre. Claims are also included for the 4 use of alkali hydroxide for a swelling agent in the process. Product claims are also included. The present case includes both product and process claims and is directed particularly to artificial silkwhich has had its natural characteristics al- 45 tered so as to produce a dull, transparent stiffer product. It also includes claims for the use of nitrogen acids in which the amount of nitric acid is greater than sulphuric acid.

The ennobling of cotton fibres by means of cotton fibres or regenerated cellulose is acted upon by a swelling agent the swelling action or the structural change brought about in the fibre is dependent upon certain factors, 1. e., concentration of the swelling agent and time .of treatment, and with most swelling agents upon the temperature of the agent, as is now well known. If the concentration is too low the swelling action will not take place in a given fibre, no matter how prolonged the time of treatment may be, and also 10 if the concentration is sumoient to produ..e the desired eifect on a particular fibre when applied for a suilicient time, if not applied for a sufficient time there will be no or substantially no swelling action. Likewise utilizing a suitable concentration for the desired eiIect on a particular fibre,

if the time of treatment is too long the particular fibre may be destroyed or spoiled. As is also now understood, variations in temperature of most of the swelling agents permit of variations in one or both of the other factors-concentration and time of treatment.

The degree of capability of a swelling treatment to attack or alter cellulose fibres, I will designate for brevity d convenience herein as the severity of treatment. For example, if sulphuric acid of say 54 B. is allowed to act at a given temperature upon a-previously mercerized cotton fabric for say 5 seconds,- and a certain swelling action is obtained, the severity of such treatment will be less than one utilizing the sulphuric acidat a concentration of 58 B. and at the same temperature for the same duration; the severity of treatment being measured by the extent to which the fibres are attacked by the treatment.

Now I have discovered that swelling treatments which are of suitable severity for producing desirable swelling actions on natural cotton fibre or fabric, are too severe for the treatment of 4o artificial silk (regenerated cellulose) and will destroy the same, but that such artificial silk can be successfully treated'with swelling agents to produce various desirable permanent effects provided the severity of treatment with the swell- 4 ing agent is less than that capable of producing any or any substantial swelling action on the ordinary or natural cotton fibre or fabric.

While it is impossible to specify the exact factors, i. e., concentration, time of treatment and temperature, for every desired effect on the artificial silk, due to the numerous variety of effects that may be desired and the various conditions under which the artificial silk is to be treated, nevertheless, in view of the foregoing general rule taken in connection with the specific examples of treatments and other information hereinafter given, those skilled in the art will be able to determine the swelling agent and the desired factors of time, concentration andtemperature for the treatment of any particular artificial silk (regenerated cellulose) for a particular finish or effect.

According to this invention valuable changes on artificial silk can be produced by means of ,swelling agents, whereby novel characteristics,

not known before on artificial fibres, are obtained. Such swelling agents are: alkali-hydroxide of concentrations as generally used for mercerization, 1. e. of a density of above 10 B., sulphuric acid of a density of above 42 B., phosphoric vacid of a density of above 50 B., muriatic acid of a density of above 20 B., nitric acid of a density of above 35 B., as well as mixtures of the above-mentioned acids; concentrated salt solutions, 1. e., chloride of zinc solution of a density of above 50 B., calciumrhodanic solution of a density of above 25 B., copperoxideammonia solution with at least 0.3% copper content; but from the commercial standpoint the most desirable of these swelling agents for treating artificial silk are, caustic soda, sulphuric acid, nitric acid and the nitration acid mixtures. Additional substances as proposed for the mitigation of the reaction can also be added to these agents; among which substances are includedone and more univalent and multivalent alcohols heterocyclic bases, formaldehyde and ammonia salts.

In treating artificial silk during longer or shorter periods according to the kind and concentration of the swelling agents, and in conformity with the prevailing operating temperatures, the same loses a part of its excessive lustre and quite in contrast to the reflection of light which is otherwise predominant above everything else, it becomes transparent. or translucent; and gradually an effect develops similar to the known transparent or glass like batiste effects on cotton. If desired by means of variations in the concentration temperature and time of action anyintermediate grade between the high lustrous character of the original material and the dull, glass-like transparent, stiff, final product can be obtained.

By such treatments the artificial silk obtains new characteristics unknown before. It has been discovered that just at the beginning of the action, when no extensive swelling has taken place, and hence almost the full lustre is still present, especially in fabrics of artificial silk, an unexpected equalization of the fabric structure takes place, thus causing the unpleasant stripes, which very often appear in artificial silk to disappear. Also if the swelling of the artificial silk is not continued beyond the permissible measure, then a remarkable increase of the tensile strength is observable; this is due to surface adhesion of the single fibres or filaments.

Each of the mentioned reagents alters artificial silk in a similar manner as above described; that is, they all act to increase the stiffness and translucency 'of the artificial silk fabric, and many of them to reduce or entirely eliminate the excessive lustre. But, in the use of nitrating acid (a composition containing varying propor-- tions of sulphuric and nitric acid with varying aqueous content) widely varying and different effects are produced depending upon the ratio of the nitric acid to the sulphuric acid and upon the aqueous content of the mixture.

For example, if the nitrating acid has an aqueous content below 20%, then quite difierent effects are produced upon the artificial silk depending upon whether the nitric acid content or the sulphuric acid content predominates. For example if more nitric than sulphuric acid is present the result will be an entirely lustreless non-translucent product; whereas if the sulphuric acid predominates the result will be a voluminous soft rich lustre efiect of crepe-like character more nearly like natural silk. But if the nitrating acid contains 20% or more water then regardless of whether the nitric or sulphuric acid predominates, the result is similar to that with the use of the other reagents, i. e., a diminishing of the high lustre and increased stiffness and transparency.

It will thus be seen that one may produce various effects by the use of different mixtures of sulphuric and nitric acids. Such nitrated products may be subsequently treated with known denitrating means to rid them of their ready infiammability.

The manipulation. of artificial silk is mostly carried out at normal temperature, but also low temperatures can advantageously be employed, whereas in the use of salt solutions often the warming of agents, partially to above the boiling point of water, is necessary. The acting period can be from a few seconds to several minutes, according to the desired effect, in individual cases up to one hour. The fibre material is held loose or under tension in the swelling agents, depending upon the effect desired.

The process is applicable to all kinds of artificial silks of regenerated cellulose, but not to acetate silk. They may be treated loose, spun or woven or as a formation of any kind, alone or also mixed with other fibres. Also those fibres, designated as staple fibre, and products obtained by spinning of short single fibres, are susceptible to this ennoblement.

Examples 1. Bleached artificial silk fabrics are passed through caustic alkali of 20 B. for a period of 4 seconds at normal temperature and slight tension, washed out, soured with diluted sulphuric acid, thoroughly washed and dried. The fabric becomes stiff, translucent, and still exhibits a faint lustre.

2. De-sized artificial silk is passed through a bath cooled to minus 10 C. of sulphuric acid of 49 B. during 5 seconds, washed completely free from acid and dried. The fabric becomes somewhat stifier, still shows a high lustre though slightly reduced, has become slightly translucent and appears much more uniform in structure; that is to say, the above-mentioned equalization of the fabric structure is apparent.

3. Immerse artificial silk fabrics at normal temperature during 5 minutes into nitric acid period of 5 minutes in a nitrating acid mixture consisting of 5 parts nitric acid and 1 part sulphuric acid with an aqueous content of 6%, then washed and dried. The fibre becomes entirely lustreless and non-translucent.

6. Artificial silk fabrics are passed through a chloride of zinc solution of 67 B. at 40 C. dur ing a period of 10- seconds, washed out and dried. The fabric has become translucent and has lost its lustre. Those skilled in the art will observe from a consideration of the foregoing five specific examples of treatments according to the present invention, that in each case the factors of concentration, temperature and duration of treatment are so chosen that the severity" of treatment is insufficient to produce anyor any substantial swelling action on natural cotton fibres. Taking for illustration the treatment of Example 1-while the caustic alkali is of ordinary mercerizing strength yet the period of treatment is but four seconds at normal temperature as contrasted with the duration of treatment of from 8 to 12 seconds for mercerizing.

If the above named swelling agents are allowed to act upon localized portions of fabrics, which containartificial silk, these portions are effected, producing contrast between treated and untreated portions, which is enhanced by dyeing due to different aifinities for certain dyes.

This fact can be of use for producing patterned effects. The local action of,the swelling means can be done by laying on the same directly, by printing, blowing or painting, with or without thickening means, reserves can be applied and the fibre material consequently immersed in the swelling means. Dyestuffs can be added to the reserves, by which a local color efiect can be produced together with the reserve.

The process can be used on all kinds of material made of artificial fibres consisting of regenerated cellulose. Materials made of artificial silk mixed with natural vegetable and animal fibres can be thereby treated.

In treating mixed materials it has been discovered, that it is advantageous for producing soft effects if the natural fibres, such for example as cotton, are worked up in the grey condition and are only cleaned or bleached after the local action of the swelling agents thereupon. By this means the end is attained that the natural fibres, in consequence or their natural incrustations, are not so quickly affected by the swelling agents,

' i. e., are not affected during the time required for altering the regenerated fibres, and therefore retain their original construction. If artificial fibres and both raw and already disintegrated natural fibres are employed side by side in mixed fibres, the variety of the efiectsis further increased, a result that makes itself evident particularly in subsequent dyeing.

Such features of my invention as to product and process, not herein claimed, are the subject of copending applications Ser. Nos. 161,022 filed January 13, 1927, 364,335,.364336 and 364,338 each filed May 18, 1929.

The term mineral acid" as used in the claims is intended to include both nitric and sulphuric acids.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

Where in the appended claims I use theterin f 1. Process for producing a novel character of.

artificial-silk which comprises subjecting the artificial silk to the action of nitration acid containing more nitric acid than sulphuric acid, the nitration acid having an aqueous content of less than 20% and capable of rendering the silk substantially non-translucent and non-lustrous and maintaining the action of said acid at a sumcient concentration for a suflicient time until the silk has become substantially non-translucent and non-lustrous.

, 2. A process for producing a novel character of artificial silk which comprises subjecting the artificial silk to the action of a mixture of nitric and sulfuric acids consisting of approximately five parts of nitric acid andorie part of sulfuric acid with an aqueouscontent of about 6% and maintaining the action for a few minutes until the silk has become substantially lustreless and nontranslucent.

3. A process for producing a novel character of artificial silk which comprises subjecting the artificial silk to the action of a nitration acid mixture containing about five parts of nitric acid to one part of sulphuric acid with an aqueous content of less than 20%, and maintaining the action until the silk has become substantially lustreless and non-translucent.

4. Fibres composed substantially entirely of artificial silk treated so as to remove at least one of the following characteristicsz-lustre, translucency, by subjecting the silk to the action of a nitration acid mixture containing more nitric acid than sulphuric acid and having an aqueous content of less than 20% and of a severity substantially incapable of swelling natural cotton fibre.

CERTIFICATE 0F CORRECTION.

Patent No. 1,998,578., v April 23, 193s.

. GEORGES HEBERLEIN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 34, for "directly" read directed; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 25th day oi June; A. D. 1935.

Bryan M. Battey (Seal) Acting Commissioner of rjPatents. 

